Digital subtraction angiography (DSA) is a well-established modality for the visualization of blood vessels in the human body. A serious disadvantage of this technique, inherent to the subtraction operation, is its sensitivity to patient motion. The resulting artifacts frequently reduce the diagnostic value of the images. Over the past two decades, many solutions to this problem have been put forward. In this paper, the authors give an overview of the possible types of motion artifacts and the techniques that have been proposed to avoid them. The main purpose of this paper is to provide a detailed review and discussion of retrospective motion correction techniques that have been described in the literature, to summarize the conclusions that can be drawn from these studies, and to provide suggestions for future research.

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Retrospective motion correction in digital subtraction angiography: a review

In an attempt to evaluate the possible usefulness of transmission computed tomography, CT scans of the chest of a series of dead dogs were obtained by means of an EMI body scanner. The sections thus obtained with and without the injection of contrast material reveal a great deal of cardiac morphology. Infarcts of the heart produced prior to scanning were imaged as regions of lower x-ray attenuation. The hearts of a series of live dogs following infarction were imaged by means of a positron emission transverse tomomograph (PETT) following administration of C-palmitate. The images permitted assessment of the relative size of the infarct. The relative advantages of transmission and emission tomography in cardiac visualization are discussed.

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Computed tomography of the heart.

A variety of periodic and aperiodic psyiologic motions affect the quality of CT images. This study was initiated to estimate what an optimal scan period should be in the design of CT units. Ultrashort scan periods were experimentally similated in the heart and liver to approximate the parameters of future technology.

https://www.ajronline.org/doi/pdfplus/10.2214/ajr.127.1.11

The effects of biological motion on CT resolution

A method has been devised to measure regional myocardial blood flow in man. The approach consists of selective injection of xenon-133 into a coronary artery and the external monitoring of radioisotope washout curves from multiple areas of the myocardium with a multiple crystal scintillation camera. Rate constants of isotope washout are calculated using a monoexponential model, and the capillary blood flow rates in multiple regions of the heart are calculated by the Kety formula. The pattern of perfusion rates is related to the coronary arteriogram obtained in the same study. Myocardial perfusion patterns obtained in patients with and without coronary artery disease and during atrial pacing are given, as well as examples of results obtained in myocardial aneurysms, in regions of ischemic myocardium supplied by collateral vessels and after tracer injection into an aortocoronary bypass graft. Advantages of the method are discussed along with limitations related to the tracer, the scintillation camera, the form of mathematical analysis and the three dimensional nature of the heart.

Measurement of regional myocardial blood flow in man: description and critique of the method using xenon-133 and a scintillation camera.

Currently available noninvasive techniques are unable to rapidly assess artery patency and tissue viability during acute myocardial infarction. In prior studies, rubidium-82 (Rb-82), a short-lived positron emitter obtained from a generator, was validated as an indicator of flow with a model that included the rate constants for transfer into and out of the cell. Accordingly, in the current study, 20 open-chested dogs with experimental infarction were studied serially at base line, after coronary occlusion, and at reperfusion. Time-activity curves acquired with beta probes on the epicardial surface were used to measure flow and net transfer of rubidium. Flow decreased to 0.41 +/- 0.08 ml/min per gram during occlusion and increased to 2.73 +/- 0.56 ml/min per gram in potentially viable ischemic tissue, whereas flows were 0.32 +/- 0.08 during occlusion (P less than 0.05 vs. viable) and 1.58 ml/min per gram (P less than 0.002 vs. viable) in irreversibly injured tissue. The transfer rate constant for Rb-82, kT, at base line was +1.22 +/- 0.60 X 10(-3) s-1 and did not change significantly during occlusion in viable vs. nonviable samples (+1.41 +/- 1.27 vs. +0.93 +/- 1.51 X 10(-3) s-1, respectively), except that 4 out of 11 nonviable tissue samples had negative kTs. At reperfusion, viable myocardial samples were all positive (+1.26 +/- 1.58 X 10(-3) s-1), whereas all irreversibly injured tissues had a negative kT, indicating leakage of tracer (-1.50 +/- 1.10 X 10(-3) s-1, P less than 0.001). This study suggests that Rb-82 time-activity curves can be useful to determine patency of an infarct related artery and potential viability after reperfusion during myocardial infarction.

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Kinetics of rubidium-82 after coronary occlusion and reperfusion. Assessment of patency and viability in open-chested dogs.

The application of digital subtraction angiography (DSA) for imaging of the human cardiovascular system is described using new, specifically designed research equipment. The system provides the ability to obtain real time or off-line subtraction images from digital data. Results show that DSA, performed by the intravenous injection of contrast material, can provide images comparable to conventional angiography in multiple areas of the cardiovascular system and on an outpatient basis.

https://www.ajronline.org/doi/pdfplus/10.2214/ajr.135.6.1153

Digital Subtraction Angiography Of The Human Cardiovascular System

To establish an innocuous method for evaluating myocardial ischemia, a technique was devised utilizing a scintillation camera to record the distribution of 43K in the myocardium following an intravenous injection of the tracer. The objective was achieved by determining with the camera the fraction of the total amount of injected material deposited in the myocardium and calculating the total myocardial blood flow as a fraction of cardiac output according to the indicator fractionation principle. Following in vivo measurements in dogs, the entire heart was excised, compared with an aliquot of the injected dose as a standard, and assayed by a well scintillation counter. Reasonable agreement was achieved between estimations determined in vivo and those determined in vitro. Because of difficulties in ascertaining the heart border on the scans, a deconvolution program which used a digital computer was applied to the 40 x 40 matrix of digitized scan data to sharpen the transition between counting levels and improve the distributional image of 43K deposition in the myocardium.

William J. Maclntyre

Papers

Digital Subtraction Angiography Of The Human Cardiovascular System

Measurement of Total Myocardial Blood Flow in Dogs with 43K and the Scintillation Camera

Gated computed tomography of the heart

Camera-computer systems for rapid dynamic imaging studies